Advances in medicine such as new diagnostic techniques require highly sophisticated bioreactors, microelectronics, microelectrodes, and biomolecular analysis techniques, for example for use in sensitive biosensors. Powerful analytical techniques such as scanning probe microscopy (SPM) have been developed, along with powerful tagging techniques in which very small structures called nanotags, are used to identify larger molecules such as biomolecules. The detection of nanotags and biomolecules using these powerful analytical techniques requires binding of the nanotags and biomolecules to substrates that are anatomically flat and sometimes highly hydrophobic, which are difficult surfaces for nanotag and biomolecular binding. Thus, a need exists for methods and compositions that can be used to facilitate binding of nanotags and biomolecules to anatomically flat and hydrophobic substrates.
In general, attachment and binding of biomolecules such as peptides and polypeptides to specific materials and substrates involve, for example, chemical adsorption and hydrophobic/hydrophilic interactions, or chemical reactions such as binding of a thiol group of a peptide to gold. However, often peptide or polypeptide binding to a very hydrophobic and atomically flat surface is very difficult often resulting in denaturization or conformational changes of the peptide structure. Presently no good solutions for reliable binding of peptides or polypeptides to such surfaces are known. For example highly ordered/oriented pyrolytic graphite (HOPG) is a popular and common substrate used for holding deposits of samples for SPM scanning. However, peptides and polypeptides tend to be non-uniformly deposited after being dried without any specific protocols. Thus, a need exists for peptides that specifically bind to atomically flat surfaces, and for methods to identify these peptides.